Tensile and fatigue properties of two titanium alloys as candidate materials for fusion reactors

Titanium alloys have been identified as candidate structural materials for the first wall, the blanket and the magnetic coil structures of fusion reac tors. Titanium alloys are interesting materials because of their high speci fic strength and low elastic modulus, their low swelling tendency and their fast induced radioactivity decay. Other attractive properties are an excel lent resistance to corrosion and good weldability, even in thick sections. Furthermore titanium alloys are suitable for components exposed to heat loa ds since they have a low thermal stress parameter. Titanium alloys with an a structure are believed to have a good resistance against radiation embrit tlement and alpha + beta alloys should possess the best tolerance to hydrog en embrittlement. Two classical industrially available alloys in the two fa milies, the Ti5Al2.4Sn and the Ti6Al4V alloys have been used in this study. The tensile properties between room temperature and 450 degreesC are repor ted. A low cycle fatigue analysis has been performed under strain control a t total strain ranges between 0.8% and 2% and at a temperature of 350 degre esC. The microstructure of both alloys was investigated before and after bo th types of deformation. Both alloys exhibit excellent mechanical propertie s comparable to or better than those of ferritic martensitic steels. (C) 20 00 Elsevier Science B.V. All rights reserved.